The invention relates to drill chucks and in particular to their method of assembly and has for its object to provide an improvement in or modification of the invention claimed in U.S. Pat. No. 3,810,642, dated May 14, 1974.
According to one aspect of the invention, there is provided an improvement in or modification of the invention claimed in U.S. Pat. No. 3,810,642, dated May 14, 1974, according to which a drill chuck is provided with a body part in which jaws are slidably mounted for converging movement in respective guides; a nut member rotatably mounted on the body part but axially located in a circumferential groove encircling said body part, said nut member having screwthreaded engagement with said jaws for advancing said jaws through a forward portion of the body part to grip a drill shank; a gear element with which the teeth of an extraneous chuck key may be engaged to tighten or slacken the jaws; and a cylindrical or generally cylindrical sleeve formed separate from, but connected to, said gear element and extending rearwardly of the body part to rotatably engage a cylindrical portion of the body part remote from the nut member, the improvement or modification residing in the fact that at least one passage extends from an axially extending bore in the body part to the circumferential groove in which the nut member is rotatably mounted, the arrangement being such that the moving parts of the chuck can be lubricated by forcing lubricant into said axially extending bore under pressure so that it can pass through said at least one passage into said circumferential groove. Preferably, a plurality of passages will extend from said axially extending bore to said circumferential groove.
According to another aspect of the invention, there is provided a method of assembling a drill chuck as described above, the method including the assembly of the component parts in dry condition, that is to say, free of lubricant, followed by the forcing of lubricant under pressure into the axially extending bore in the body part so that lubricant passes through the passage or passages communicating with the circumferential groove in which the nut member is rotatably mounted. The method may include the connection of the cylindrical sleeve to the halves of the nut member or to the gear element, or to the halves of an integral nut and gear element, purely by pressing them together or by the use of an adhesive.